The present invention relates to an internal combustion engine, and to a method of operating an internal combustion engine.
Applicants' pending published application US 2005/0022790 A1 discloses an internal combustion engine to which fuel/air mixture is supplied via an intake channel into the crankcase from a carburetor. Opening into the intake channel is a fuel opening that supplies fuel to the intake channel as a function of the underpressure in the intake channel. The fuel opening is supplied from a fuel channel in which is disposed a switching valve that is actuated as a function of the speed of the internal combustion engine.
During idling of such an internal combustion engine, a small quantity of mixture is supplied via the intake channel to the crankcase during each revolution, and from there is transferred via the transfer channels into the combustion chamber. Due to the small quantity of fuel, and the conditions in the combustion chamber, a combustion of the mixture in the combustion chamber cannot occur during each revolution. If combustion is not effected, a portion of the noncombusted fuel is scavenged out of the combustion chamber by the mixture that subsequently flows out of the crankcase. There thereby results an increased consumption of fuel during idling, and worsened emission values.
It is therefore an object of the present invention to provide an internal combustion engine of the aforementioned general type that has a low consumption of fuel and low exhaust gas values during idling. It is a further object of the invention to provide a method of operating an internal combustion engine by means of which low exhaust gas values can be achieved during idling operation.